Permissions, Privileges, and Access Controls
The Organic Groups (OG) module 7.x-2.x before 7.x-2.3 for Drupal allows remote authenticated users to bypass group restrictions on nodes with all groups set to optional input via an empty group field.
CWE-264 - Permissions Privileges and Access Controls
CWE 264 (permissions, privileges, and access controls) is not a weakness in and of itself, rather it is a category of weaknesses related to the management of permissions, privileges, and other security features used to perform access control. If not addressed, the weaknesses in this category allow attackers to gain privileges for an unintended sphere of control, access sensitive information, and execute arbitrary commands.